MTI-1 board

[skippyfix]

When my machine tool changes when I use m25 or m6 the mti-1 board will not come back on with out me pulling one of the fuses out of the board ? It is a new board and the machine has a new spindle motor, does anybody have any ideas what I can try??? I have had this mill for three months and have not made one part with it but have spent a lot of mony trying to get it up and running, PLEASE HELP

[machintek]

The advantage of a seasoned service engineer is that they have seen a specific problem and have put in the time to know cause, effect, and solution. I have never seen your problem. But if you give me your email address, I can forward my KTK service class notes to you. It may help.

George

[skippyfix]

Hello PM sent Thanks

[skippyfix]

I noticed on my new MTI-1 card the two resistors numbers R11 and R12 are 330 ohms 5 watts on the old board they are 150 ohms 5 watts would this cause the problems?

[skippyfix]

Hello all, I have set my machine to the KTK service class notes and now the MTI-1 board will work when i do a tool change, but when I just let the spindle run for about a hour and try to do a tool change the MTI-1 board will not start with out me pulling the fuse on the MTI-1 board, then it will run again but I can not do a tool change, after about 6 hours of running the board goes off and every time I pull fuse and put back in light on MTI-1 board only stays on for about 15 seconds? I have checked the board with a infrared temp gun and nothing is very hot on the board I have also opened cabinet and put a big fan in front of it to see if that helped but did nothing for the problem, anybody have any suggestions?????????? Thanks

[gandalf69]

Have you checked the spindle motor thermal overload?

[mflux_gamblej]

When I ran my spindle with the brake on (I have a problem with my machine where the auto brake doesn't work) the MTI-1 board blew it's SCR. that's the big black thyristor with the heat sink.

One symptom was that I could run the motor, but it would shut down after an hour or two. The interesting thing was that the MTI-1 board would shut down whether the spindle was running or not. It was a strange OL type of behavior. If the spindle was running when it shut down, the whole breaker OL would trip. If the spindle was not running, the MTI-1 seemed to be on OL, couldn't reset it, but after an hour or so, I could fire the machine back up.

I expect that some piece is on thermal OL.

Go through your MTI-1 board and inspect the electronics with a multimeter. If you need help testing your SCR, follow my guide in another post here: http://www.cnczone.com/forums/bridge...eed_after.html

Replace what's broken. The only component on that board that's hard to replace is the transformer. Everything else is available on Mouser or at a local electronics junk yard.

I hate the MTI-1, but it's a very simple PCB at least. I managed to repair my system, and have been making parts for a couple of weeks now - spindle runs > 8 hours/day sometimes with no interruptions.